Yamaha 2 stroke
- Thread starter perattzi
- Start date
Thanks dudes! I hope to have it on the road by Halloween...with it being Halloween-y colors and all. Head surfaces are being cut and chambers reshaped to more modern design. Then rebore and Pro-X pistons. No port work this time around...it will be plenty fast for now I hope. After that I just need some intake manifolds, a seal/gasket set, and a regulator/rectifier unit....so yea tons more :
Ok here is a bit of paint I finished the other day.
I sanblasted the triples and lower cover, handlebar mounts, gauge assemblies, and the headlight shell and mounting ears. Then prime, color, clear coat. For the orange parts, I then sanded from 800 up to 2000 and followed with 2 different grades of polish and then wax. The tank was sandblasted and painted as well but is still awaiting decals and clear coat. Keeping this thing clean is going to be full time job!
I also took the time to route my hand control wires through the clubmans...which was a major pain in the ass but looks a treat! Most of the wiring is back together. However, there are a few mystery wires I need to sort out.
Oh and I took on the little task of rebuilding the oil pump...still working on that
Made some other parts nice and shiny too! I'm finally getting the hang of doing a proper polishing job.
I sanblasted the triples and lower cover, handlebar mounts, gauge assemblies, and the headlight shell and mounting ears. Then prime, color, clear coat. For the orange parts, I then sanded from 800 up to 2000 and followed with 2 different grades of polish and then wax. The tank was sandblasted and painted as well but is still awaiting decals and clear coat. Keeping this thing clean is going to be full time job!
I also took the time to route my hand control wires through the clubmans...which was a major pain in the ass but looks a treat! Most of the wiring is back together. However, there are a few mystery wires I need to sort out.
Oh and I took on the little task of rebuilding the oil pump...still working on that
Made some other parts nice and shiny too! I'm finally getting the hang of doing a proper polishing job.
What is the leakdown issue and what pressure/vacuum are you using? It should be done at around 6 PSI and you need to plug both sides - the lab seal in the crank center allows air to leak from one side to another when it's not running. If Scott CLough rebuilt that crank and you fitted new seals on both ends of the crank, you are unlikely to have a leakdown problem.
Yamaha twins for years use two outer seals and one center lab seal between the two center bearings. That one is aluminum and is a non-contact seal which seals when the motor is running but allows a leak when static.
DG pipes are pretty good for a basic street pipe and dirt cheap to boot. Forget all that Stinger BS. In simple terms stinger diameter effects pipe temperature and performance as it goes over the peak. Smaller is OK on a race bike but will probably melt your pistons on the street. Y boot and K&N is a smart choice. Forget carbon reeds. Tests show that the only decent reeds on an RD on the street are Boyesens and the difference vs stock is really really small.
When you set up the jetting, err on the side of rich and work down. Most usual mode of seizing is part throttle lean condition coupled to too much advance.
Boink was right that RD400 is even better than the 350 and an RZ is much better than either, but that's not what you have so spend teh time getting your bike spot on and enjoy it.
Yamaha twins for years use two outer seals and one center lab seal between the two center bearings. That one is aluminum and is a non-contact seal which seals when the motor is running but allows a leak when static.
DG pipes are pretty good for a basic street pipe and dirt cheap to boot. Forget all that Stinger BS. In simple terms stinger diameter effects pipe temperature and performance as it goes over the peak. Smaller is OK on a race bike but will probably melt your pistons on the street. Y boot and K&N is a smart choice. Forget carbon reeds. Tests show that the only decent reeds on an RD on the street are Boyesens and the difference vs stock is really really small.
When you set up the jetting, err on the side of rich and work down. Most usual mode of seizing is part throttle lean condition coupled to too much advance.
Boink was right that RD400 is even better than the 350 and an RZ is much better than either, but that's not what you have so spend teh time getting your bike spot on and enjoy it.
i am using a leakdown tester that I built myself. I have both exhaust and the left intake plugged...on the other intake I have the tester i made up. Here I'll just post a pic:
I think I will get another rubber expansion plug to block off the manifold instead of the pvc elbow. At first my manifolds were leaking like crazy but I fixed that. Now, I can't find the leak when I pressurized to 6 psi using a bicycle pump. i spray windex everywhere but no bubble. it may be my tester but I dont see any bubbles there either. All seals are OEM and all bolts are torqued to spec. Also, the heads have been converted to o-rings instead of copper gaskets.
My buddy has a RD400, it's awesome after the mods he has done. Really I think it's just preference. The 400is better for the street probably, the power delivery is more smooth, and less vibration. But it is heavier and somewhat less rigid b/c the engine is rubber mounted to the frame. Also, parts such as con rods are super expensive on the 400 compared to the 350. Really I'd like to have one of each and an RZ! But RZ's go up in price daily it seems.
I think I will get another rubber expansion plug to block off the manifold instead of the pvc elbow. At first my manifolds were leaking like crazy but I fixed that. Now, I can't find the leak when I pressurized to 6 psi using a bicycle pump. i spray windex everywhere but no bubble. it may be my tester but I dont see any bubbles there either. All seals are OEM and all bolts are torqued to spec. Also, the heads have been converted to o-rings instead of copper gaskets.
My buddy has a RD400, it's awesome after the mods he has done. Really I think it's just preference. The 400is better for the street probably, the power delivery is more smooth, and less vibration. But it is heavier and somewhat less rigid b/c the engine is rubber mounted to the frame. Also, parts such as con rods are super expensive on the 400 compared to the 350. Really I'd like to have one of each and an RZ! But RZ's go up in price daily it seems.
Thanks diesel! The motor was the kick in crotch of this project. Hopefully, it will be money well spent.
Cost breakdown:
- crank(bearings, rods, labor etc.) $450
- pistons, bore, head machining(heads are set up for o-rings now too!) $550
- misc parts, paint, gaskets etc... about another $150
- electronic ignition $289
so yea alot of money
whole built is easily over 3 grand at this point...not counting endless hours of labor(fun).
Cost breakdown:
- crank(bearings, rods, labor etc.) $450
- pistons, bore, head machining(heads are set up for o-rings now too!) $550
- misc parts, paint, gaskets etc... about another $150
- electronic ignition $289
so yea alot of moneywhole built is easily over 3 grand at this point...not counting endless hours of labor(fun).
Can you explain how that tester works, or I guess how you mount it? I assume you mount it then just pump air in and look for leaks. Does it just mount to the carb intake boot? I would bet that if you can't find a leak any where else you have a slow seep right there.
Also, you should throw a how to on making that tester up in the $50 mod thread.
Also, you should throw a how to on making that tester up in the $50 mod thread.
Nice little leak down tester. If it holds 6psi you are good to go.
Why did you go with O rings? Copper will usually seal OK with a thin smear of gasket goo. Do you have a good source for the O rings - I'm assuming we're talking copper or stainless O rings or pressurized WIlls rings, not rubber right?
Why did you go with O rings? Copper will usually seal OK with a thin smear of gasket goo. Do you have a good source for the O rings - I'm assuming we're talking copper or stainless O rings or pressurized WIlls rings, not rubber right?
No it loses pressure...I wish it would hold 6 psi. Still waiting on my new reeds, then I will redo my testing, once I get a good seal I dont want to mess it up by having to install reeds b/c the intakes can lead a ton, take some fiddling with torque and yamabond to get a good seal there. As for the o-rings, they are some sort of rubber-ish material. I get them from: http://home.earthlink.net/~scloughn/index.html , the guy who did all of my engine work. He very reputable in Yamaha and Kawasaki 2 stroke circles.
Finally got the engine to hold pressure! held 6psi for 10+ minutes. I installed some modified YZ125 reeds...the racing reeds I bought were much too stiff for any kind of low rpm riding. So on the up and up...just have to button the clutch side up, install my new ignition and fix some other wiring. Just in time for the dead of winter :'(.
Diesel, and whomever else is interested: I did a write up on building and using a 2 stroke leakdown tester like mine. I added it to the $50 mod thread. Hopefully, it will help someone out, it's good insurance and will make tuning and jetting wayyy easier and more accurate.
SCR have a good reputation.
Thanks for that leakdown tester info. I have two professional testers and they give very different readings from one to the other.
FYI Rick Mehar at Accu-products in OH does a ton of RD and TZ work, and Bill Bune in MN is my go to guy for cranks now. They are cost effective and fast.
I don't get O rings for sealing compression. That doesn't make any sense at all. My TZs have O rings to keep the water out and no gasket to keep compression in. We used to lap the heads and barrels for a perfect fit.
But you are where you are, so keep moving forward. That's a nice Dyna ignition conversion
Thanks for that leakdown tester info. I have two professional testers and they give very different readings from one to the other.
FYI Rick Mehar at Accu-products in OH does a ton of RD and TZ work, and Bill Bune in MN is my go to guy for cranks now. They are cost effective and fast.
I don't get O rings for sealing compression. That doesn't make any sense at all. My TZs have O rings to keep the water out and no gasket to keep compression in. We used to lap the heads and barrels for a perfect fit.
But you are where you are, so keep moving forward. That's a nice Dyna ignition conversion
Teazer, do you have pics of your TZ's on the web?? Would love to see them...
As far as the o-rings for the heads, I was having the surfaces refaced and Scott C suggested that I change to o-rings to help with the squish. I said sure go for it as it wasn't much more cost wise. I sent him an email today asking about the advantage over the copper gaskets. Quote:
"The O-rings are silicone rubber, you could also use Viton. You can get replacements if needed from a Parker store or other suppliers like Mcmaster-Carr, # 2-039, or I should have them in stock. They conform better to any irregularites, and can flex and adjust like piston rings. I've been doing more motors that way, and they have worked very well, even in the roadracers.
Also, with the thick 350 gaskets, we can't get the squish down as tight as desired, a minimum of about .055" compared to .030"-.035". Eliminating the gasket allows the squish to be set as desired."
Most all liquid cooled 2 strokes I have seen use o-ring heads...and if the orings work the same or better then that's great b/c they're alot cheaper! 8)
All I need is a reg/rec and throttle cable before I can fire my bike up. But too bad it's like 9 degress here in Ohio. :'(
I installed the Dyna the other day, still need to time it. My buddy has a dial gauge with the correct adaptor...I should have done that when the motor was out of the frame...oh well.
As far as the o-rings for the heads, I was having the surfaces refaced and Scott C suggested that I change to o-rings to help with the squish. I said sure go for it as it wasn't much more cost wise. I sent him an email today asking about the advantage over the copper gaskets. Quote:
"The O-rings are silicone rubber, you could also use Viton. You can get replacements if needed from a Parker store or other suppliers like Mcmaster-Carr, # 2-039, or I should have them in stock. They conform better to any irregularites, and can flex and adjust like piston rings. I've been doing more motors that way, and they have worked very well, even in the roadracers.
Also, with the thick 350 gaskets, we can't get the squish down as tight as desired, a minimum of about .055" compared to .030"-.035". Eliminating the gasket allows the squish to be set as desired."
Most all liquid cooled 2 strokes I have seen use o-ring heads...and if the orings work the same or better then that's great b/c they're alot cheaper! 8)
All I need is a reg/rec and throttle cable before I can fire my bike up. But too bad it's like 9 degress here in Ohio. :'(
I installed the Dyna the other day, still need to time it. My buddy has a dial gauge with the correct adaptor...I should have done that when the motor was out of the frame...oh well.
http://pinkpossum.com/TZ250A/index.htm
http://pinkpossum.com/TZ250E/index.htm
Scott's right that they are the only solution on a water cooled race motor. It's an interesting way to adjust squish. I machine the heads and or barrels to allow for whatever gasket we are using. On your motor for example it's common to have significant differences in rod length, barrel height and piston height. On a TD3 it always ends up with selective assembly and usually involves some machining to get it all to where I want it.
But Scott knows his stuff and has a lot of records to his name.
To time that motor you can just slip the heads off and bolt the DTI on a bracket and time them up or get an adapter to go in where the plug sits.
http://pinkpossum.com/TZ250E/index.htm
Scott's right that they are the only solution on a water cooled race motor. It's an interesting way to adjust squish. I machine the heads and or barrels to allow for whatever gasket we are using. On your motor for example it's common to have significant differences in rod length, barrel height and piston height. On a TD3 it always ends up with selective assembly and usually involves some machining to get it all to where I want it.
But Scott knows his stuff and has a lot of records to his name.
To time that motor you can just slip the heads off and bolt the DTI on a bracket and time them up or get an adapter to go in where the plug sits.
Wow! Awesome bikes man...
I am aware of the manufacturing tolerances with these parts. I assume Scott measured everything and adjuster what was needed. Guess it's not safe to assume things though. Well see how it works out, if it doesn't then my cylinders are essentially expensive scrap. But I have read on 2 stroke forums that the o rings are working fine in a/c RDs. I can't wait to get this project 'done' (theyre never done), so I can start another. There is an R5 for sale pretty cheap not too far from me, if the guy would get back to me I would buy it up in a second. Thinking of another RD(or R5, YDS7 etc) but with a mono shock conversion, very similar to the l/c rear setup. I am taking a welding class next month and thought that would be a great project. R5 chassis with disc brakes/spokes and a 400 motor. I think that would be a cool setup. Also probably getting a cb350 soon as well. That one I would like to resto/customize and sell it to someone who wants a turn key bike, the motor is solid and is generally pretty nice, so it would be much lighter on the pocket. Well see...my workshop is pretty damn cold right now.
I am aware of the manufacturing tolerances with these parts. I assume Scott measured everything and adjuster what was needed. Guess it's not safe to assume things though. Well see how it works out, if it doesn't then my cylinders are essentially expensive scrap. But I have read on 2 stroke forums that the o rings are working fine in a/c RDs. I can't wait to get this project 'done' (theyre never done), so I can start another. There is an R5 for sale pretty cheap not too far from me, if the guy would get back to me I would buy it up in a second. Thinking of another RD(or R5, YDS7 etc) but with a mono shock conversion, very similar to the l/c rear setup. I am taking a welding class next month and thought that would be a great project. R5 chassis with disc brakes/spokes and a 400 motor. I think that would be a cool setup. Also probably getting a cb350 soon as well. That one I would like to resto/customize and sell it to someone who wants a turn key bike, the motor is solid and is generally pretty nice, so it would be much lighter on the pocket. Well see...my workshop is pretty damn cold right now.
Thanks.
Scott knows what he's doing and probably measured everything he needed to measure. You can always check your squish clearance to be sure and I assume Scott gave you a figure to set the timing to that he recommends for the work he did. It's probably around 1.85mm on 93 Octane gas or maybe he set the motor up for 89 Octane.
Scott knows what he's doing and probably measured everything he needed to measure. You can always check your squish clearance to be sure and I assume Scott gave you a figure to set the timing to that he recommends for the work he did. It's probably around 1.85mm on 93 Octane gas or maybe he set the motor up for 89 Octane.
